Disposable garments, principally disposable diapers, extensively utilize adhesive fastening tabs to effect closure of the garment. Adhesive fastening tabs have gained widespread popularity due to their versatility, cost, and advantages over older conventional type fasteners, such as safety pins, snaps or zippers.
A typical commercial adhesive fastening tab has two separate attachment ends, one end permanently attached to the garment and one "free" end placed by the user. The user placed end allows for adjustablity. However, this user-placed, adhesive attachment end of the fastening tab generally causes placement problems prior to its use. The free adhesive end must be conveniently and removably stored in a manner such that the adhesive is functional and available for use for a significant period of time after manufacture. This is conventionally done by protecting the adhesive surface of the free attachment end by adhering it to a release composition (e.g., a low surface energy polymer) coated tape.
The release coated tape can be a separate tape which covers the free adhesive end of the fastening tab prior to use. When the user wishes to place the free end of the fastening tab, the release tape is peeled away and discarded exposing the free adhesive end for closure. Examples of this approach are discussed in U.S. Pat. Nos. 3,930,502 (Tritsch), 3,970,086 (Cheslow) and 4,576,598 (Tritsch) (who uses a release coated tape which has release coating on both faces). A problem with this approach however is the need to separately dispose of the release tapes.
Another approach has been to locate the release tapes on the diaper itself at a location suitable for attaching the free end or portion of the fastening tab, yet at a place that will not interfere with attachment of the free end when the fastening tab is used. Examples of this approach are discussed in U.S. Pat. Nos. 3,985,136 (Cepuritis) (located on inner diaper face), 3,987,793 (Milnamow) (same), 3,999,545 (Milnamow) and 4,144,887 (Milnamow). This approach is advantageous in that it doesn't require a separate release tape or separate disposal of the release tape, but it is often complex in manufacture and construction.
The third main approach has been to make the release tape integral with the fastening tab. In this approach the fastening tab is folded in a manner which permits the free adhesive end of the fastening tab to be in contact with a separate portion of the same tab where a release coated surface is located. The most common method for placing a release coating on the fastening tab is to zone coat a release coating directly onto the fastening tab substrate as per U.S. Pat. Nos. 3,999,544 (Feldman et al.), 4,084,592 (Tritsch), 3,862,634 (Small), 3,950,824 (Karami), 4,050,121 and 4,097,627 (Nemeth et al.). The adhesive is also separately zone coated directly onto the fastening tab in these patents. Very often a zone coated adhesive strip is directly adjacent to a zone coated release strip. This can cause significant manufacturing problems due to the incompatible nature of release and adhesive coatings, making it difficult to coat them side by side simultaneously. For example, if the release and adhesive coatings are sequentially applied, overlapping the two strips typically causes incompatibility related problems, making the product difficult to collect as a roll.
It has also been proposed to release coat one entire side of a film which is then placed, non-coated side down, as a strip on a portion of a tape that has a full coating of adhesive, U.S. Pat. No. 4,177,812 (Brown et al). This approach allows one to readily locate a release coated surface directly adjacent to an adhesive coated surface but at a significantly greater cost in materials and handling.
Other approaches include those discussed in U.S. Pat. No. 4,237,890 (Laplanche), which discloses a fastening tab where a separate release coated strip is attached directly to the fastening tab using a narrow strip of glue separate from the pressure-sensitive adhesive on the tab; U.S. Pat. No. 3,853,129 (Kozak), which discloses using a retiform surface that serves as a release layer (i.e., by providing a low adhesive contact area), and U.S. Pat. No. 4,670,012 (Johnson) which proposes eliminating a release surface by using an adhesive with a low peel force. These approaches are generally not desirable from a manufacturing, cost and/or performance perspective.